Understanding and measuring coordination and control in kicking skills in soccer: implications for talent identification and skill acquisition

In this review, we explore the role of motor control and biomechanics in developing an understanding of soccer skills using kicking as the main vehicle. The links between these sub-disciplines of sport science have not been well established in the past because of an emphasis on cognitive processes in traditional accounts of motor behaviour. We argue that a dynamical systems interpretation of the processes of coordination and control in movements with multiple degrees of freedom signals a new era in the relationship between the sub-disciplines of motor control and biomechanics. Although research on coordination and control of soccer skills is currently sparse, there are indications that the relationship between motor control and biomechanics could form a significant component of scientific programmes in talent identification and skill development. Further interdisciplinary work is needed to enhance understanding of coordination and control of soccer skills.     

A three-dimensional kinematic analysis of the long jump take-off

The long jump has been widely studied in recent years. Two models exist in the literature which define the relationship between selected variables that affect performance. Both models suggest that the critical phase of the long jump event is the touch-down to take-off phase, as it is in this phase that the necessary vertical velocity is generated. Many three dimensional studies of the long jump exist, but the only studies to have reported detailed data on this phase were two-dimensional in nature. In these, the poor relationships obtained between key variables and performance led to the suggestion that there may be some relevant information in data in the third dimension. The aims of this study were to conduct a three-dimensional analysis of the touch-down to take-off phase in the long jump and to explore the interrelationships between key variables. Fourteen male long jumpers were filmed using three-dimensional methods during the finals of the 1994 (n = 8) and 1995 (n = 6) UK National Championships. Various key variables for the long jump were used in a series of correlational and multiple regression analyses. The relationships between key variables when correlated directly one-to-one were generally poor. However, when analysed using a multiple regression approach, a series of variables was identified which supported the general principles outlined in the two models. These variables could be interpreted in terms of speed, technique and strength. We concluded that in the long jump, variables that are important to performance are interdependent and can only be identified by using appropriate statistical techniques. This has implications for a better understanding of the long jump event and it is likely that this finding can be generalized to other technical sports skills.     

The effects of changing pace on metabolism and stroke characteristics during high-speed breaststroke swimming

Performances often vary between the heats and finals of breaststroke swimming competitions possibly because the swimmers try to conserve their energy, or for other tactical reasons. Additionally, coaches might advise either a 'positive' or 'even' pace race strategy during the final. The effect of such pacing changes on metabolism (blood lactate, heart rate, ventilation), ratings of perceived exertion, stroke kinematics and turning times have not been investigated. Nine male competitive breaststroke swimmers swam three paced (Aquapacer) 200-m trials, 48 h apart and in random order, at 98%, 100% and at an attempted 102% of their maximal 200-m time-trial speed. Responses in metabolic variables were similar between the 98% and 100% trials, but higher post-exercise blood lactate concentrations and respiratory exchange ratios were observed following the 102% trial. As the pace of trials increased, stroke rate was found to increase proportionately with stroke count. However, during the latter stages of the 100% trial, a disproportionate increase in the stroke count was observed, which led to a significant pacing error. This feature was more obvious in the 102% trial, where participants demonstrated 'positive pacing' and reported higher ratings of perceived exertion than for the 98% trial. During the early stages of the trials, turning times were initially shorter the faster the pace of the trial; however, as the trials progressed, this pattern was found to reverse. We conclude that a slight reduction in pace during near maximal breaststroke swimming altered kinematic but not post-exercise metabolic responses, while an increase in pace led to positive pacing and an increase in both kinematic responses and anaerobic metabolism.     

Gastrointestinal distress is common during a 161-km ultramarathon

This study examined the incidence, severity, and timing of gastrointestinal (GI) symptoms in finishers and non-finishers of the 161-km Western States Endurance Run. A total of 272 runners (71.0% of starters) completed a post-race questionnaire that assessed the incidence and severity (none = 0, mild = 1, moderate = 2, severe = 3, very severe = 4) of 12 upper (reflux/heartburn, belching, stomach bloating, stomach cramps/pain, nausea, vomiting) and lower (intestinal cramps/pain, flatulence, side ache/stitch, urge to defecate, loose stool/diarrhoea, intestinal bleeding/bloody faeces) GI symptoms experienced during each of four race segments. GI symptoms were experienced by most runners (96.0%). Flatulence (65.9% frequency, mean value 1.0, s = 0.6 severity), belching (61.3% frequency, mean value 1.0, s = 0.6 severity), and nausea (60.3% frequency, mean value 1.0, s = 0.7 severity) were the most common symptoms. Among race finishers, 43.9% reported that GI symptoms affected their race performance, with nausea being the most common symptom (86.0%). Among race non-finishers, 35.6% reported that GI symptoms were a reason for dropping out of the race, with nausea being the most common symptom (90.5%). For both finishers and non-finishers, nausea was greatest during the most challenging and hottest part of the race. GI symptoms are very common during ultramarathon running, and in particular, nausea is the most common complaint for finishers and non-finishers.     

Examining Change in Cortisol Patterns During the 10‐Week Transition to a New Child‐Care Setting

The transition to out‐of‐home child care brings a number of challenges for children, including complex peer interactions and extended separations from parents. Children often show a midmorning to afternoon rise in cortisol on child‐care days, compared to the typical diurnal decline seen at home. Changes in cortisol were examined in a wide age range of children (N = 168; 1.2 months to 8 years, M = 3.27 years) during the 10‐week transition to a new child‐care setting. Structural equation modeling using latent change scores showed that children experienced an increase in the cortisol rise at child care across the 10‐week transition. Furthermore, child age moderated the difference between home‐ and child‐care cortisol patterns. Findings are placed in a developmental context, and potential implications and future directions are discussed.     

Effects of an Attachment‐Based Intervention on Child Protective Services–Referred Mothers' Event‐Related Potentials to Children's Emotions

This study examined the neurobiology of maternal sensitivity to children's emotions among mothers involved with Child Protective Services (CPS) and low‐risk comparison mothers (M_age = 31.6 years). CPS‐referred mothers participated in the Attachment and Biobehavioral Catch‐up (ABC) intervention or a control intervention. Mothers' event‐related potentials (ERPs) were measured while they categorized images of children with crying, laughing, and neutral expressions. CPS‐referred ABC mothers (n = 19) and low‐risk comparison mothers (n = 30) showed a larger enhancement of ERP responses for emotional faces relative to neutral faces than CPS‐referred control mothers (n = 21). Additionally, the magnitude of ERP responses to emotional faces was associated with observed maternal sensitivity. Findings add to the understanding of the neurobiology of deficits in parenting and suggest that these deficits are changeable through a parenting intervention.     

The relationship between motor skill proficiency and body mass index in preschool children

The purpose of this study was to examine the relationship between motor proficiency and body mass index (B/MI) in preschool children. Thirty-eight children ages 4-6 years had their BMI calculated and were assessed using the Movement Assessment Battery for Children-2 (MABC-2; Henderson, Sugden, & Barnett, 2007). These data were analyzed in two ways. The correlation between BMI and MABC-2 percentile ranks was calculated. Next, the groups were subdivided based on BMI status (high, M = 85.5; medium, M = 49.8; low, M = 10.8), and compared using t tests to determine if differences existed in MABC-2 percentile ranks. No significant relationship existed between MABC-2 and BMI percentile ranks (r = -.237). However significant differences in MABC-2 percentile ranks existed between high and low (p = .042), and high and medium (p = .043) groups. These results suggest that preschool children classified as overweight or obese may have lower motor proficiency than their normal weight and under weight peers. This study indicates there is a direct relationship between motor proficiency and BMI in the preschool population.